The present invention relates to electrical box mounting behind drywall or any wall type, e.g., plywood and in particular to an adjustable depth box extender for electrical boxes.
Drywall is generally accepted as an interior wall material. The drywall may be attached to wood or metal frame structures and is available in various thicknesses. The electrical box is mounted behind the drywall and a mud ring is attached to the face of the electrical box and reaches through the dry wall. Electrical devices are attached to the face of the mud ring and are intended to line up with the face of the drywall. Complicating mud ring selection, there are a myriad of different wall configurations mandated by engineers to address structural, code and other design requirements.
Even if the electrical contracting professional installs the correctly sized mud ring for a specific application, e.g. ⅝″ for one layer of ⅝″ drywall, irregularities in wall construction, final finish (i.e. the addition of ceramic tile on the face of the drywall), and occasional damage to the bracket that secures the junction box will result in the face of the mud ring not being flush with the final face of the constructed wall.
Complicating matters further, sometimes the correctly sized mud ring is not commercially available for specified wall construction; for instance, major manufacturers do not produce a mud ring that is designed for a wall 1¾″ thick.
Ensuring the mud ring is flush is not only an aesthetic concern, but more importantly an electrical code requirement: the National Electrical Code, Article 314.20 demands that the space from the face of the wall to the face of the mud ring not exceed ¼″.